Protective element for a breakwater or wave-retarding construction

ABSTRACT

A protective element for a breakwater or wave-retarding construction comprises a body that has at least two opposing projections. The projections are on either side of a flat base and extend transversely thereto. The periphery of the base is non-circular, so that rolling of the protective element under the influence of the beating of the waves is resisted.

The invention relates to a protective element for a breakwater or wave-retarding construction, comprising a concrete body that has at least two opposing projections.

A protective element of this type is disclosed in NL-A 8903138. Such protective elements are intended for the parts of, for example, breakwaters, dams and the like that are exposed to the beating of the waves. The waves break as soon as they strike the protective elements, with the result that the underlying parts are better protected against the forces of the water.

The protective elements are usually made of concrete. Usually no reinforcement is used on the grounds of durability. Although a reinforcement has a beneficial effect on the strength of the protective element, it nevertheless has the disadvantage that rusting can hardly be prevented, especially in a salty environment. This means that the strength of the protective element has to be provided by the concrete material alone. It is therefore necessary to choose as advantageous as possible a shape for the protective element. Despite the lack of reinforcement, it must nevertheless be possible to ensure adequately high strength by this means.

The aim of the invention is therefore to provide a protective element of the abovementioned type that has an as advantageous as possible cohesion and strength. Said aim is achieved in that the projections are on either side of a flat base and extend transversely thereto. Preferably, the projections are in the middle of the base. Furthermore, they can have all conceivable shapes; a cylindrical shape and a conical shape are mentioned as examples.

The projections are preferably oriented perpendicularly with respect to the base. Furthermore, the base can have at least one auxiliary projection at the periphery which extends parallel to or in line with the base.

The base as well can have various shapes. A non-circular shape, such that the protective element will not easily start to roll under the influence of the water forces, is preferred. The base is preferably polygonal, preferably rectangular, pentagonal or hexagonal. For ease of production a peripheral shape based on a regular polygon is preferred. There can be an auxiliary projection at each corner of the base.

Just like the base, a projection can have various peripheral shapes. A non-circular shape is preferred because of the resistance to rolling. The periphery of a projection is preferably polygonal. One possibility is that the periphery of a projection is a regular polygon, just like the periphery of the base. If the peripheral shapes are of identical shape, in the case of a polygon with n corners the preference is that the polygon of the projection is turned through the order of 360/2n degrees of an arc with respect to the polygon of the base.

Another preferred embodiment for the shape of the projection is that the end terminates in a flat surface. In this context it is preferable that this surface is virtually perpendicular to a longitudinal axis of the projection.

The material from which the element is made is preferably concrete, which contains at least cement, sand, granulate or gravel and optionally hardeners and/or plasticisers. Another preferred embodiment of the material is a material that at least consists of a residue from oil refining, sand, rock-like granulate or gravel. Such a material is known under the trade name C-Fix®. This can be compared with a sort of cement-bound concrete, where the cement has been replaced by a residue from oil refining, the melting point of which is above 150° C.

A possible method for producing a protective element using this material is as follows. The material is heated to above the melting point of the residue material from oil refining. This material is introduced into individual shuttering or casting moulds for the base or projections, after which said material is allowed to cool. A protective element is then assembled by locally heating the joining end of a projection and the joining location on the base. The projection and base are then brought together and the join is allowed to cool, as a result of which a permanent join is produced.

Another preferred embodiment of the base of the protective element is that this has two parallel surfaces.

Another possibility for production of a protective element is to produce this in a split shuttering. For this purpose a raised area is made on the ground, after which a split box is placed on this elevation. This box split by a vertical plane has a bottom box which is open at the top and the bottom. The open bottom fits over the elevation in a sealed manner. A top box is attached to the bottom box, which top box can be moved relative to the bottom box.

Material for the element is poured via the open top of the bottom box, as a result of which the base and at least a bottom projection is formed, the bottom of this projection being on the elevation. After the material has set to some extent, material is poured into the top box for the top projection. After all the material has set, the top box is raised a short distance using lifting means, which are between the bottom box and top box, for freeing the material and the box. The bottom box is then lowered a short distance, which is less than the distance travelled by the top box, to free the box. This lowering is effected by known lifting means in the support means, such as legs which are provided with threaded adjustment means. These legs are located below each part of the bottom box. The closure means between the parts of the split box are then unlocked and the parts of the bottom box are removed together with their top box. The box can then be re-used.

The invention will be explained in more detail below with reference to a few illustrative embodiments shown in the figures.

FIG. 1 shows a perspective view of the principle of a protective element according to the invention.

FIG. 2 shows, diagrammatically, an example of the use of the protective element.

FIG. 3 shows a perspective view of a first illustrative embodiment of the protective element according to the invention.

FIG. 4 shows a plan view of the element according to FIG. 1.

FIG. 5 shows a side view of the element according to FIG. 1.

FIG. 6 shows a further embodiment of the protective element according to the invention.

FIG. 7 shows a possible production method.

FIG. 8 shows a possible variant of split shuttering for the production of a protective element.

FIG. 1 shows the basic principle of a plate-shaped base 1 and top and bottom projections 2 and 3, respectively. FIG. 2 shows protective elements which are situated on an incline of a breakwater.

The protective element for a breakwater shown in FIGS. 3-5 comprises a plate-shaped base 1, indicated in its entirety by 1, on either side of which projections 2 and 3 extend perpendicularly. The base 1 is essentially rectangular and at the four corners has projections 4 which have a pointed shape determined by the sloping surfaces 5, 6.

The projections 4 define recesses 7 between them, through which the water is able to flow freely. The polygonal, in this case square, shape of the base body 1 guarantees high stability.

The base 1 has two surfaces 8, 9 facing away from one another which are parallel to one another.

In the embodiment in FIG. 4 a plan view is shown of a hexagonal protective element provided with two hexagonal projections 2 (one can be seen in FIG. 4) as well as six projections 6.

FIG. 7 shows a possible method for the production of a protective element according to the invention. For this purpose a first recess 11, defined by shuttering 12, is made in a substrate 20. A first quantity of concrete 13 is poured into this shuttering 12, up to ground level 10, to form a first projection of the protective element to be produced.

A second shuttering 14 is produced on the ground 10, into which a second quantity of concrete 15 is then poured to produce the base. It is also possible to wait until the second shuttering 14 has been produced on the ground 10 before pouring the first quantity of concrete 13. The quantity of concrete 13 and 15 can then be poured in a single operation, as a result of which the bottom projection and the base are produced at the same time.

After this base has set to some extent, third shuttering 16 is placed on top of this to receive a quantity of concrete 17 that is to form the top projection.

After the quantities of concrete 13, 15, 17 have set, the protective element is complete.

FIG. 8 shows another shuttering for the production of an element from FIG. 3-5. This shuttering consists of two halves split by a vertical plane. FIG. 8 a shows a box in the closed state, in which the element will be released from the box. The bottom box 21 consists of a left-hand bottom box 23 and a right-hand bottom box 24, which are open at the top and at the bottom. The top box 22 connected to the bottom box 22 by the connecting means 29 consists of a left-hand top box 25 and a right-hand top box 26. Lifting means are incorporated in the connecting means 29 to enable the top box to be lifted with respect to the bottom box. At least three support means 30 are positioned below the bottom box, which support means can be provided with wheels. Known lifting means are incorporated in the support means 30 to enable the bottom box to be lowered. The bottom of the top box is provided with a left-hand and a right-hand apron 27 and 28, respectively, which lies on the top of the poured material for the base of the element and ensures good abutment and correct rounding-off between base and top projection. The poured element 1 with the left-hand and right-hand half of the shuttering removed can be seen in FIG. 8 b. 

1-23. (canceled)
 24. Protective element for a breakwater or wave-retarding construction, comprising: a plate-shaped base (1) which has two parallel surfaces (8, 9) facing away from each other, said base (1) having a periphery defined by a regular polygon, an auxiliary projection (4) being provided at each corner of the base (1), said auxiliary projections (4) having a pointed shape defined by sloping surfaces (5, 6), as well as a projection (2, 3) at, and extending from, the middle of a respective surface (8, 9) of the base (1).
 25. Protective element according to claim 24, wherein the projections (2, 3) are in the middle of the base (1).
 26. Protective element according to claim 24, wherein the projections (2, 3) are in the extension of one another.
 27. Protective element according to claim 24, wherein the projections (2, 3) are oriented perpendicularly with respect to the base (1).
 28. Protective element according to claim 24, wherein the base (1) has at least one auxiliary projection (4) at the periphery, which auxiliary projection extends parallel to or in line with the base (1).
 29. Protective element according to claim 24, wherein the periphery of the base (1) is non-circular.
 30. Protective element according to claim 29, wherein the periphery of the base (1) is square or rectangular.
 31. Protective element according to claim 24, wherein the periphery of the base (1) is polygonal.
 32. Protective element according to claim 31, wherein the periphery of the base (1) is a regular polygon.
 33. Protective element according to claim 30, wherein there is an auxiliary projection (4) at each corner of the base (1).
 34. Protective element according to claim 24, wherein the periphery of a projection (2, 3) is non-circular.
 35. Protective element according to claim 34, wherein the periphery of a projection (2, 3) is polygonal.
 36. Protective element according to claim 35, wherein the periphery of a projection (2, 3) is a regular polygon.
 37. Protective element according to claim 24, wherein both the periphery of the base (1) and of a projection (2, 3) is a regular polygon.
 38. Protective element according to claim 37, wherein a regular polygon, with n corner points, of a projection (2, 3) is of identical shape to a regular polygon of the base (1) and that the polygon of said projection (2, 3) is turned through the order of 360 divided by 2n degrees of an arc with respect to the polygon of the base (1).
 39. Protective element according to claim 34, wherein the end of a projection terminates in a flat surface.
 40. Protective element according to claim 24, wherein the material from which the element is made is concrete.
 41. Protective element according to claim 24, wherein the material from which the element is made comprises at least a residue material from oil refining, sand, rock-like granulate or gravel.
 42. Protective element according to claim 24, wherein the base (1) has two parallel surfaces (8, 9).
 43. Method for the production of a protective element according to claim 24, comprising the following steps: creating a first cavity (11) in a substrate (20) provided with shuttering (12) for a first projection (2), optionally pouring concrete into the first shuttering (12), creating a second shuttering (14) on the ground (10) above the first shuttering (12), pouring concrete (15) into the second shuttering (14) on the ground (10) and the previously poured concrete (13) for the first projection, or simultaneously pouring concrete (13) into the first shuttering (12) and pouring concrete (15) onto this and the ground in the second shuttering (14), allowing the quantity of concrete (15) in the second shuttering (14) to set to some extent, placing a third shuttering (16) on the concrete (15), set to some extent, within the second shuttering (14). pouring a quantity of concrete (17) into the third shuttering (16) to form the second projection.
 44. Method for the production of a protective element according to claim 24, wherein the material at least consists of a residue material from oil refining, sand and rock-like granulate, comprising the following steps: separate production of base (1) and projections (2, 3) by: heating said material to above the melting point of the said residue material, pouring the material into a shuttering, allowing the material to set by allowing it to cool; locally heating the joining end of a projection (2, 3) at the same time as locally heating the base (1) at the joining location for said projection (2, 3) to above the melting point of the residue material, bringing said projection (2, 3) and the base (1) together at their joining location and then allowing the heated portion of the material to cool, as a result of which a permanent join is produced.
 45. Method for the production of a protective element according to claim 24, comprising the following steps: making a raised area on the ground (10) this area having a cross-section that corresponds to the cross-section of a bottom projection, fitting a split bottom box (21), which is open at the bottom and open at the top, on the raised area together with a split top box (22) connected to the bottom box (21), pouring the material for the element into the bottom box (21), allowing this material to set to some extent, pouring the material into the top box (22), allowing the material to set, after which the top box is moved upwards a short distance such that the top box is freed from the material, lowering the bottom box (21) a short distance, which is less than the distance travelled by the top box (22), such that the bottom box (21) is freed from the material, removing one half of the bottom box (23) with top box (25) and then the other half of the bottom box (24) with top box (26), after which bottom box (21) together with the top box (22) can be re-used for the production of a subsequent element.
 46. Shuttering for the production of a protective element according to claim 24, which consists of a bottom box (21) split in a vertical plane, with a left-hand bottom box (23) and a right-hand bottom box (24), and a top box (22) split in the same vertical plane and connected to the bottom box (21), wherein the bottom box is open at top and bottom and can be placed with the bottom over an elevation in a sealed manner and that the top box (22) is connected to the bottom box (21) by connecting elements, wherein lifting means are incorporated in said connecting elements so as to raise the top box (22) with respect to the bottom box (21) and wherein the bottom box (21) is supported by support means, for example mobile legs, which are provided with lifting means so as to lower the bottom box together with the top box. 